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Sipping the Waters: Techniques for Selecting Untreated Backcountry Water for Drinking

Drinking untreated backcountry water can make you sick - but choosing your drinking spots intelligently can greatly reduce that risk. Here, a doctor shares the methods that have kept him healthily "sipping the waters" for the past 20 years.

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by Michael von Gortler, MD | 2006-09-20 03:00:00-06


Sipping the Waters: Techniques for Drinking Untreated Backcountry Water - 1
A hot May day in the Indian Peaks Wilderness just to the west of Boulder, Colorado.

June, 2006. My friend Padre is a minister, a cleric from Ohio, and we get together most years for a backpack in the high country. As we load up packs at the trailhead for the Never Summer Mountains in Rocky Mountain National Park, I ask Padre if we dare leave the water filter behind. We’ve decided to use only unfiltered water on this trip, but he says we should carry the filter just in case. So I toss it in my pack. Throughout the trip we enjoy cold and very pure natural waters - with no gut wrenching regrets later - and the filter remains in the pack, unused.

I’ve often felt a nice connection to the natural world that comes from reaching right down into a stream and sipping handfuls of icy water on a hot day. I make it a regular part of my hiking practice to look for good water and drink some on every hike. Over the years I’ve realized that with proper and systematic evaluation of a water source, one can probably obtain clean and pure drinking water by using careful selection criteria. This article describes the methods I use to decide which waters to sip from. I’ve been doing it continuously now for almost twenty years and never once acquired any intestinal illness during that time.

Background - Giardia in the Jarbidge

It’s only been in the last year or two that we’ve taken to sipping natural mountain waters for an entire trip. For me, coming around to this way of handling water has been a very gradual process. The first and only time that I’ve had Giardia was 23 years ago, when I was a young and naïve graduate student. Then, I’d gone on a backpack trip with a friend into the wilds around Jarbidge, Nevada, a remote area in the northeastern part of the state. The night before we entered the wilderness my friend and I had camped next to an idyllic little river. As the evening twilight settled over us, I cooked up a meal and took water from the river at our feet.

The next morning on our way to the trailhead we came around a bend in the road just upstream from our camping spot, and to my wonder a large flock of sheep proceeded to cross the road in a great cloud of dust. A sheepherder smiled at us as the last of the sheep crossed the road. My friend and I continued on to the trailhead and never gave the sheep another thought.

Trouble hit about three days later. Hiking along, my friend began to complain of stomach pains, which grew worse through the afternoon. Then the illness hit full force, and within hours we were both incapacitated. I’ll skip the messy details but the experience, as they say, is one I shall never forget.

After that awful experience of Giardia, I took it for granted that water everywhere in the backcountry has Giardia in it. That seemed to be the advice wherever I checked. For the next several years I never drank untreated water, always boiling or filtering it first before drinking. I assumed and believed all the warnings about Giardia being ever-present.

One day on a mountain hike in hot weather I ran completely out of water. As the day wore on I realized it was going to be a long, thirsty hike back to base camp before I could get any clean water. Eventually thirst drove to me to consider a drink of raw water, and I started scouting for a likely source. I finally drank from a fast-moving streamlet on a steep slope that carried snowmelt down to the valley stream below. The water was icy cold and very clear. At that point I was so thirsty I didn’t really care what happened, but I noticed after a few days that everything was fine.

Enjoying the Taste of Natural Water

I’ve often felt a nice connection to the natural world that comes from reaching right down into a stream and sipping handfuls of icy water on a hot day.

Over the years there were other opportunities to sample pure, untreated mountain water. Sometimes on high alpine slopes, especially on high ridges with melting snowbanks, I’d dip a hand into a rivulet and take a few sips. Then, it was mostly symbolic, as I wanted to have in my mountain wanderings the experience of just drinking water straight from the Earth. An interesting thing happened: I did this half a dozen times and never had any ill effect. So I began to make it a regular part of my hiking practice to look for good water and drink some on every hike. Eventually it occurred to me that with proper and systematic evaluation of a water source, one could probably obtain clean and pure drinking water by using careful selection criteria.

General Principles of Sipping the Waters

Let’s discuss a few general principles of selecting a good water source. I mainly backpack in the high Rockies of Colorado and Wyoming where snowbanks persist on mountain slopes the year round, so much of what follows is best suited to finding good water in an alpine environment. These methods may be substantially less applicable to water at lower elevations and in places where the water is not moving very fast. For example, in the canyon country of the Southwest I am considerably more cautious about the water I choose to sip.

The considerations about water purity break down into two main classes: biological impurities such as bacteria and parasites, and chemical impurities such as metals or toxins. Here in Colorado, the long history of mining in the mountains has created a number or areas where heavy metal pollution is a real concern. In this discussion I will focus mostly on the common biological contaminants such as Giardia and Cryptosporidium. Avoiding toxic impurities that result from mine tailings requires very specific knowledge of the watershed you are traveling in and is beyond the scope of this article. Normally this problem is handled by the Forest Service authorities and warnings are posted at trailheads. For example, the trailhead for the Fourteener mountain of La Plata Peak in central Colorado carries an arsenic warning for the streams that drain some old mining activity.

First Principle: Get water close to its source

How do we go about finding water with a high probability of being uncontaminated by pathogens? The single most important aspect of finding good sipping water is to get close to the source. Usually this means finding a watercourse that is draining a large snowbank high on a steep slope. While hiking along I scout the slopes above, looking for likely snowbanks that are perched in large talus slopes. These areas are typically the least visited by wandering elk or deer. Often the water coming off these snowbanks courses under the rocks for some distance and this lessens the chance of animal contact with it.

Sipping the Waters: Techniques for Drinking Untreated Backcountry Water - 2
Alpine snowmelt in the Indian Peaks Wilderness.

Second Principle: Make sure the water is cold

Test the water with your hand to see if it is quite cold. Extremely cold water barely above freezing means it has not traveled far from its icy source. Cold water does not make it harder for organisms to survive, but it means that the water has had less chance to come into contact with animals that deposit the organisms.

Third Principle: Look for fast-moving water

Standing or slow-moving water has more opportunities to acquire pathogens from the animal population. In general, look for swiftly moving water, preferably from a small source coming straight down a slope. These streamlets very often drain a melting snowbank during the warmer months. In general, I prefer to avoid sipping the water from any stream wider than four or five feet, unless I know with certainty that it comes from clean water upstream. Some of the rivers I frequent in Colorado are high enough and swift enough to drink from. I am more confident in drinking from these larger streams after I’ve successfully done it several years in a row, and I now have a large inventory of waters around the state that I consider clean and drinkable.

Sipping the Waters: Techniques for Drinking Untreated Backcountry Water - 3
Spring runoff in the Indian Peaks Wilderness. Fast-moving water has less opportunity to acquire pathogens from the animal population. Look for water from a small source that is nearby to further improve quality.

Fourth Principle: Take water that is naturally filtered

I often drink water that is flowing down a forest slope that has lots of vegetation. Here the trick is to seek water that is moving fast and is very cold. I look for a streamlet that has very thick brush growing either side of it, meaning that animals have less access to the water. I have come to believe that lots of moss growing on the rocks in the streamlet is a good sign. It seems to correlate with a high degree of filtration as the moss acts like a kind of sponge, filtering out minerals, dirt, and small bits of debris.

Sometimes I find that good water comes from seeps. A seep is a narrow space in a rock wall that permits a slow movement of water out to its surface. Often you can find a good flat wall of rock with hanging moss gardens and nice clean water seeping from a crack in the rock. This water typically is being filtered through layers of rock and sand above the seep. Just be sure to survey the slope above the seep to make sure there are no obvious elk wallows. Some of the best tasting and cleanest appearing water I’ve found in Canyon Country comes from seeps. Here, the water is being filtered through hundreds or even thousands of feet of sandstone and is likely extremely pure.

Sipping the Waters: Techniques for Drinking Untreated Backcountry Water - 4
Seeps from rocks will likely have water that has been filtering down for years if not much longer.

Fifth Principle: Avoid large mammals

Once in a while my water-sipping strategies backfire, sometimes in a funny way. Once after climbing a high peak in Rocky Mountain National Park I was descending a talus slope in a scantly used drainage. Walking along the tundra I found a likely looking streamlet with the all the requisite qualities. I walked along for a while, looking for elk sign as elk are numerous in this Park. After scouting for a quarter mile and seeing no sign of elk, I bent down and slaked my considerable thirst with the icy cold water. I resumed the march downhill and came around a bend to see four of the largest and most magnificent bull elk I’d ever seen. Each one had an enormous trophy rack of points - they were quite a gang of stately bulls. They were grazing five feet away from the stream I’d just drunk from! I waited nervously for a few days to become sick with Giardia, but luckily nothing ever happened.


Another important consideration is our friend the beaver. Colorado and Wyoming have large beaver populations, and one needs to be on the lookout for them. Sometimes I’ve followed a stream that I considered a good candidate for sipping, only to find a beaver lodge a ways upstream. I’ve sometimes come across many beaver dams in a single creek, spread out over a mile or more. In these areas the stream water should be avoided.


The presence of livestock in areas visited by backpackers can be a problem. This is a thorny political issue but also an ecological and health issue, as cattle may spread pathogens such as Giardia. Unlike elk and deer which wander over very large distances, cattle are often confined to a single watershed and may contribute greatly to fouling of waters. The best approach here is to be aware of any livestock operations in the areas one is visiting. I rarely sip any waters in these areas unless I can clearly see the entire watercourse from its direct source in a snowbank.

Closing Comments

The methods outlined here will help you to survey an area and decide whether drinking natural waters is prudent. Besides offering an option on long hikes when you may not have a filter along, sipping natural waters provides certain spiritual satisfactions and improves the wilderness experience. I feel a lot closer to the natural world when I can move around the mountains and partake of her natural offerings.

Although there will always be some element of risk in sipping natural waters in the wilderness, clearly this risk has been overstated for many years. Some readers may feel that the strategies presented in this article are unreliable or unduly risky, but they have served me well for nearly twenty years. During that time I’ve refined my methods for assessing water quality and have never once gotten ill from sipping water this way. (Of course, keep in mind that despite my precautions and calculations, a healthy immune system and a bit of luck surely play a part in my success too.) For me as a woodsman and mountaineer, being able to eat native wild plants and sip wild natural water is an important part of my life activities. With some intelligent study and thoughtful testing, many people will be able to enjoy the satisfaction of sipping natural waters. Good luck!

About the Author

Sipping the Waters: Techniques for Drinking Untreated Backcountry Water - 5
The author atop Fremont Peak in the Wind River Range, the second highest point in Wyoming.

Mike von Gortler is a middle-aged but active guy who lives in Boulder, Colorado where he is close to vast expanses of backcountry. He's been practicing as an Emergency Physician for the past 18 years. The pursuit of wild chanterelles and other edible mountain plants keeps him moving through the uplands while keeping an eye out for the wildlife and wildflowers. Several times a year he can be found atop a Fourteener with his teenage daughter or some friends.


"Sipping the Waters: Techniques for Selecting Untreated Backcountry Water for Drinking," by Michael von Gortler, MD. (ISSN 1537-0364)., 2006-09-20 03:00:00-06.


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Sipping the Waters: Techniques for Selecting Untreated Backcountry Water for Drinking
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Mike Clelland
(mikeclelland) - MLife

Locale: The Tetons (via Idaho)
Selecting Untreated Backcountry Water for Drinking on 08/04/2009 22:14:54 MDT Print View

I love this article!

Michael Swanson
(wutzmyname) - F

Locale: Northern California
Re: Sipping the Waters: Techniques for Selecting Untreated Backcountry Water for Drinking on 08/05/2009 17:22:44 MDT Print View

Great article. It certainly proved invaluable during my hike through Desolation Wilderness in Tahoe last week.


Nate Meinzer
(Rezniem) - F

Locale: San Francisco
Wait two weeks on 08/05/2009 18:08:46 MDT Print View

Then you'll know for sure....

Glenn Douglas
My experience in South America. on 04/16/2010 20:30:29 MDT Print View

I have been hiking in South America for about the last year and a half. I have drank all water untreated from Santiago south to Ushuaia and never had any problems on either side of the Andes.

However in Peru and Bolivia I did. I used a katadyn mini water filter and had problems for the first three treks in the following areas.
Bolivia - Cordillera Real - Choro trek and Sorata Area.
Peru - Ausungate Circuit.

I then switched to using Chlorine tablets and did not use the water filter for treating all water including cooking water and had no further problems in either country.

I believe the problems come from livestock (llamas) grazing even at high altitudes in Peru and Bolivia. Its hard to get closer to the source than the animals do.

I will use chlorine tablets in Peru and Bolivia in future.

Ted E
(Mtn_nut) - MLife

Locale: Morrison, CO
Re: Re: Sipping the Waters: Techniques for Selecting Untreated Backcountry Water for Drinking on 04/17/2010 14:01:39 MDT Print View

I personally think all water should be pre-filtered at least with something similar to a coffee filter. i've hiked into the indian peaks wilderness, and while i think the water would probably safe to drink on the west side of the divide, pre-filtering it keeps bugs and other stuff out of the water.

Also, now with things like the steripen, all my water will be sterilized with UV light, and then i can still get fresh tasting water without having to take a chance of getting very sick in a remote place...

Edited by Mtn_nut on 04/17/2010 14:02:52 MDT.

obx hiker
(obxcola) - MLife

Locale: Outer Banks of North Carolina
frontier pro on 04/17/2010 14:44:31 MDT Print View

Hi Frank,

Per your post: "I notice that McNett has introduced the Aquamira Frontier Pro Filter, which appears to be exactly what I was looking for last year. Namely, something that filters worms and other large parasites but isn't so fine as to clog easily. I'll be using this on future trips."

I have had positive and negative experiences with the frontier pro; recently having it clog up from suspended solids from what could fairly be considered fairly pristine sources within 200 verticle feet of the uppermost ridge. Maybe I was getting suspended leaf mold that would be less of a problem once things greened up but the water appeared to be VERY clear and was coming out of the ground within sight. (this was late March, southern appalachians)I'd pre-fiter with a bandanna or something and be careful! If the little cotton type pre-filter disk clogs you'd better have a back-up or you to will be drinking al fresco sans filtro or whatever.

I'm in the process of making a home-made amigo pro

Buck Nelson
(Colter) - MLife

Locale: Alaska
Anecdotal or scientific? on 09/27/2014 12:20:00 MDT Print View

Let me lead off by saying that water treatment is a personal choice.

That said, the author's rules are not backed with good data. The author suggests looking for cold water, while other authors point out that giardia cysts survive longer in cold water, making it more risky. The author suggests using fast moving water, some have suggested lakes are safer as giardia cysts tend to sink in calm water. The author suggests avoiding main streams, other authors say main streams are safer because "dilution is the solution." The point is, these are theories without solid data to back them up.

It is human nature to believe in our own experience. In threads like this there are usually people who've gotten giardia after drinking backcountry water. I'm one of them. Will someone's experience match mine, or someone who has never gotten sick? There's no way of knowing.

The EPA says Cysts have been found all months of the year in surface waters from the Arctic to the tropics in even the most pristine of surface waters. Another quote from that paper Hibler (1988) found Giardia cysts in 19% of springs. Look at that paper and do a search for "pristine" and see how often giardia is found in even pristine waters.

Some people can build some immunity over time to various waterborne diseases, but there are many strains of giardia. I've had giardia three times and it's easy to find tales from other hikers who have been stricken multiple times over many years, just as it's easy to find hikers who rarely or never treat and have never gotten sick.

The incubation period of giardia is usually 3-25 days, but can be as little as 1 day. The Dr's reported onset was on the 4th day after drinking the suspect water.

Sheep DO sometimes carry a strain of giardia that can infect humans, as can many other species of animals.

"Giardia and crypto are also easily shaken off by a healthy adult." Sometimes. Sometimes not. Several backpackers appear weekly at Centinela Mammoth Hospital in Mammoth Lakes sick enough with giardiasis to need urgent care

"Incidentally, there is no reason to get too worried about cow manure near the water." ...animal manure can carry many pathogens ranging from Giardia to Salmonella to E. coli. Here's a fact I recently uncovered: Giardia-infected cattle excrete nearly 100 million Giardia cysts per day Dr Robert Derlet.

Unfortunately while researching this I was saddened to learn that the author of this article, along with his daughter, lost their lives in the Colorado mountains in 2011.

Edited by Colter on 09/27/2014 12:23:43 MDT.